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E. CAREY, H. GASKELL, Jr., 8v F. HURTER.

PROCESS 0F MAKING SUDIUM SULPHITE.

Patented June 3-0, 1885.

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EUSTACE CAREY, HOLBRCOK GASKELL, JR., AND FERDINAND HURTER, OF VIDNES,COUNTY OF LANCASTER, ENGLAND.

PROCESS OF VMAKING S'ODlUlVl SULPHITE.

SPECIFICATION forming pari; of Letters Patent No. 321,341, dated June30, 1885.

Application filed May 20, 1885. (No specimens.) Patented in England JuneQ6, 1884. No. 9,458.

'To @El whom may concern,.-

Be it known that we, EUsTAcE CAREY, HoLBRooK GAsrruLL, the younger, andDINAND HURTER, alkali manufacturers, subjects of the Queen of GreatBritain and Ireland, and of the Republic of Switzerland, respectively,and residing at Vidnes, inthe county oi' Lancaster, England, havejointly invented certain improvements in the Manufacture ci' Sulphite ofSoda, (for which we have made application in Great Britain, No. 9,458,dated June 26, 1884,) oi' which the following is a specification.

Our invention has for its object the manufacture at a low cost ofsulphite of soda suitable for use in the manufacture of paper or forother purpose to which it may be applicable. According to our saidinvention we employ in the said manufacture of sulphite of soda 2Osalts,77 meaning thereby monohydrated car bonate of soda. The said saltsmay, for the purposes of our invention, be obtained in any suitableway-such, for example, as by evaporation by heat of those solutions ofsoda named in the specifications of the British Letters Patent grantedto Eustace Carey, Holbrook Gaskelhdr., and Ferdinand Hurter, on the 18thday of July, 1879, No. 2,939, the 11th day of January, 1881, No. G08,and

the 17th day of March, 1881, No. 1,161, the

said alkaline solutions having been rst purified by the processes namedin the specifications of the said Letters Patent, or for certainpurposes where color and purity are not of importance the salts may bethose obtained in 'the Le Blanc process by the evaporation by heat ofthe solution of crude carbonate of soda, known as vat-liquor77 ortank-liquor, or they may be salts obtained by the to evaporation by heatof other solutions of carbonate of soda. To the said salts, by whichevermethod obtained, we add, if necessary, a small quantity of water or ofsteam and expose the said salts in suitable vessels to the .i5 action ofsulphurous-acid gas obtained in any convenient way-for example, byburning sulphur or pyrites. This treatment of the salts withsulphurousacid gas is continued until they are sufficient-1y convertedinto sulphite of soda, which is applicable for use in the manufacture ofpaper or other purpose where it is not necessary that the sulphiteshould be of a high test, as although the said sulphite is very readilyand cheaply manufactured by the process constituting our in- Vention, ashereinbefore described, it will not be uncontaminated with bicarbonateof soda or other impurities, but these impurities will not render thesulphite of soda unsuitable for use for certain purposes-such, for 6oexample as for employment in the manufacture ot' paper.

Ve do not limit ourselves to any particular forni of apparatus in whichto carry on the process according to our invention, as any suitableapparatus may be employed for this purpose; but we will describe formwhich is suitable for the purpose. It is shown in the annexed sheet ofdrawings in side elevation in Fig. 1, and elevation in Fig. 2, and 7oplan in Fig. 3. The iron cylinder A (which,

if sulphite oi' soda oi' great purity is required, may be lined withlead) is capable of being rotated upon a horizontal axis. The cylinderis provided with hollow trunnions or axes supported by and capable ofturning in bearings a, carried by a suitable frame-work, a?. The hollowtrunnion at one end of the cylinder A is used for admittingsulphurous-acid gas, and that at the other end for permitting 8o theexit of excess of sulphurous acid, of carbonic acid, of nitrogen, and ofmoisture. The said hollow trunnions are continued by pipes entering intothe interior of the cylinder and there turned at or about right anglesto the axis of the cylinder A, as shown at b, for the purpose ofavoiding the lodgnient therein of solid material, and the consequentstoppage of the free passage ofthe gas into or from the cylinder A.

Ve find it advisable to have an aperture in the cylinder A and in theexit-pipe C, as shown at e e, which apertures can be closed airtight inany convenient manner, and through the said aperture which is in thecylinder, the part b of the exit-pipe C,which is in the cylinder A,maybe cleaned easily and freed from d ust, which is sometimes depositedthere.

Having described a forni of apparatus suited for the purposes of ourinvention, we will pro- IOO ceed to describe the method of working whichwe find advantageous. rlhe charge of salts is introduced into thecylinder A through an aperture provided for that purpose, which is thenclosed. The cylinder is made to revolve slowly by any suitablemeans-i`or example, by means of -a pulley, F, and spur-gearing G drivenby any suitable motor. Ve find from two to siX revolutions of thecylinder per minute are sufficient. Sulphurousacid gas is admitted intothe interior of the cylinder A by the pipe y, and the sul phurous acidis absorbed by the charge.

The progress of the operation may be ascertained by withdrawing andtesting a sample from time to time. We nd that whenasample contains fromthirty-six to forty per cent. of sulphurous acid, the productpractically answers all the purposes of a monosulphite of soda, and theprocess is then stopped and the charge withdrawn. lf strongsulphurousacid be used, such as is obtained by treating sulphuric acid with cokeor with sulphur, one such cylinder A is suflicient, but when sulphurousacid mixed with nitrogen is used, as

it is when obtained by the combustion in at! mospheric air of sulphur orpyrites or sul phureted hydrogen, then the absorption is not complete inone cylinder, and the gases leaving the cylinder A by the exit-pipe Cstill contain sulphurous acid. These gases may be passed through one ormore cylinders similarly constructed, and so arranged that any one'ofthem may be connected directly to the source of supply of sulphurousacid, or be made to receive the gases from another cylinder of theseries, or be isolated for discharging and charging, as required; or thegas escaping from the cylinder A may be passed into a sulphuricacidchamber. If the sulphurous acid be Obtained by the combustion of pyritesor brimstone, it is advisable to pass it through a dust chamber beforeallowing it to enter the cylinder A, so that any dust may be rstdeposited. If the sulphite of sodaY be desired of great purity, it isalso necessary to wash the su1- phurous acid by passing it through asmall tower, U, Fig. 3, lined with lead and lled with coke. The gaspasses in an upward direction through the tower and meets a very smallstream of hot water. When the gas has thus been washed it must be dried.For this purpose the gas passes in an upward direction through a similartower, V, lled with coke, where the gas meets a stream of sulphuric acidwhich absorbs the moisture; but when great purity of the sulphite ofsoda is not required we omit the Washing and drying ofthesulphurous-acid gas, except when it is obtained by the combustion in airof sulphureted hydrogen, in which ease the gases must be dried. Vhen thecylinders are worked in series, it may be found necessary to dry the gason passing from one cylinder to the next. For this purpose the gas maybe passed through a coketower, V, as before described, which may beplaced between the cylinders, or the gas may be dried in any otherconvenient manner.

Having now particularly described and ascertained the nature of our saidinvention and in what manner the same is to be performed, we declarethat what we claim is The manufacture of sulphite of soda by exposingsalts to the action of sulphurous-acid gas, substantially ashereinbefore described.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

EUSTACE CAREY. HOLBROOK GASKELL, JR. FERDINAND HURTER.

'Vitnesses:

RICHARD MERCER, JOHN FARRANT,

Both of Widnes.

